I received a sample spool of Mettler with an order a couple years ago. It seems like decent thread but it's a little thicker and lintier than I prefer for piecing. I use Aurifil or Precensia for piecing and any quilting I want to vanish (SITD).
For decorative topstitching and quilting that I want to have stay visible I find Connecting Threads to be just the ticket. It's a bit lintier but it's so cheap I can afford to have at least one spool of every single color on hand, and it's good strong thread. It's thicker so it stays visible on top of the quilt. I'm so happy they've added variegated threads to their lineup, I love using those for meanders. AND I noticed they've finally fixed my biggest gripe - now they're numbering the spools themselves instead of just the packaging, so you can know what a color is once you've opened it. That doesn't help with 90% of the thread I've already bought but I'm still glad they finally fixed that.